This invention relates to an impression data-processing apparatus which reads out a 4-bit coded data denoting a numeral and an 8-bit coded data indicating a letter from a memory and later printing both forms of data.
Where data is processed, for example, by an electronic computer, the processed data is impressed, for example, by a line printer. An impression instruction is issued in the form specifying the prescribed column of a bill. An impression data supplied to a printing device is formed of a word data corresponding to each column and a space data for specifying the column. Where a memory is supplied with serially arranged words whose length is variable, then a space data is defined according to a maximum number of columns included in a bill and a number of numerals or letters constituting a word impressed in the respective columns.
There will now be described the manner in which data being impressed on a bill by a printing device are processed. Where an impression data is only formed of numerical data other related information, then one digit can be formed of 4 bits. Where, however, an impression data is formed of a letter, then it is impossible to represent the character by 4 bits. Generally, one character is formed of 8 bits. Actually where an impression data includes numerical data and letter data, not only letter data but also numerical data and other related information normally expressible by 4 bits are all denoted by 8 bits. Therefore, all impression data recorded in a disk or tape are formed of 8 bits. Where impression data are actually processed by an electronic computer, the letter is regarded to be formed of a combination of 4-bit units denoting numerals and can be processed, for example, by the CPU. Namely where an impression data is processed can be handled as information having 4 bits. "A character data of 8 bits" is simply an assumption to distinguish a letter from a numeral. In actual printing, it serves the purpose if a letter is handled in a unit of 8 bits. Data being actually impressed on a bill are mostly formed of space data, numerical data and other datas related to a numeral. At present, a disk, memory and tape include a considerable number of bits which should be prevented from being recorded. This condition noticeably decreases the recording capacity of such recording media.